Cutting 10 Round Tubes

So I've been gearing up this season to use my T9 and always seem to waste the two balls that don't fit in the magazine from the 10 round tube. Anyone have any suggestions for cutting down 10 rnd. tubes to hold 8 balls? Going out for the first time this season on sunday and i would like to cut down a couple before the weekend.

I use a capless harness that is pretty hard to get the 10 round tubes in the correct way. That or i always seem to drop those extra paintballs. and after 4 ten rounds thats a magazines worth of paint i've lost. I'd simply prefer to have a couple 8 round tubes and some 10 rounds for when i bring out my phantom